A wide variety of different types of equipment have been developed for sealing pressure activated adhesive (primarily pressure activated cohesive) business forms, and particularly mailer type business forms, such as shown in U.S. Pat. Nos. 5,174,493 and 5,201,464. The equipment developed includes edge sealing rolls which engage only the edge portions of the forms which contain the pressure activated cohesive, or steam roller type rollers which engage the entire forms (where inserts are not used), and often various types of turning mechanisms between sets of rolls so as to seal patterns of adhesive having different orientations. Typically such equipment applies a sealing force of at least 100 pounds per lineal inch, typically about 200 pounds per lineal inch.
In U.S. Pat. Nos. 5,938,880 and 5,944,946 a method and apparatus are disclosed that allow both the xe2x80x9chorizontalxe2x80x9d and xe2x80x9cverticalxe2x80x9d patterns of cohesive of mailer type business forms to be sealed in a single pass but without the crushing action provided by steam roll type equipment. While the method and apparatus in those patents is highly useful, it normally effects sealing of the same patterns of adhesive at a number of different locations, and is limited in its ability to adapt to different locations of the patterns of pressure sensitive cohesive on particular forms.
The method and apparatus according to the present invention allow the same advantages as the method and apparatus in U.S. Pat. Nos. 5,938,880 and 5,944,946 as far as being able to effectively seal both vertical and horizontal patterns of pressure activated adhesive in a single unidirectional path and without utilizing a steam roller action which can crush inserts or portions of the form between the patterns, but does so with greatly enhanced versatility, and also in a very cost effective manner. This enhanced versatility and cost effectiveness are provided by utilizing two different sets of rolls. The first set includes a first roll that is substantially continuous but a second roll which is non-round and has projection portions which are the only portions of the roll that can effectively seal with the first roll. The second roll is controlled by a stepper motor, in turn controlled by a microprocessor, so that a projection of the second roll can be brought into operative association with the first roll whenever desired, whether at a regular interval or irregular interval, in order to effectively seal a pressure activated adhesive pattern which is substantially parallel to the axes of rotation of the rolls. A second set of rolls, for sealing pressure activated adhesive patterns that are substantially perpendicular to the axes or rotation of the first set of rolls, is preferably provided substantially immediately adjacent the discharge from the first set of rolls, and includes a continuous roll and a pair of rolls that cooperate with the continuous roll (second and third rolls) and which are on a substantially common axis. The positions of the second and third rolls with respect to each other and the first roll may be adjusted so as to accommodate different widths of forms (spacings between the pressure activated cohesive patterns to be sealed by the second set of rolls). No further sealing equipment is necessary.
According to one aspect of the present invention there is provided a method of sealing a business form having pressure activated adhesive including a first pattern in a first dimension, and a second pattern in a second dimension substantially transverse to the first dimension, comprising: (a) Moving the form in a direction substantially parallel to the second dimension; and while practicing (a). (b) At only a first location, automatically applying at least about 100 pounds per lineal inch of pressure to the form at the second adhesive pattern to seal the form at the second adhesive pattern substantially without engaging any other portion of the form. And (c) at only a second location, spaced in the direction of movement of the form, automatically applying at least about 100 pounds per lineal inch of pressure to the form at the first adhesive pattern.
Typically (b) is practiced using a first set of rolls including a first substantially continuous roll having a length greater than the length of the second adhesive pattern, and a second roll having a non-round shape with at least one projection having a length greater than the length of the second adhesive pattern and comprising the only part of the second roll cooperating with the first roll to seal the first adhesive pattern. Also typically (c) is practiced using a second set of rolls including a first substantially continuous roll and a second substantially continuous roll, the second set of rolls aligned with the first adhesive pattern of the business form.
When the form comprises two first substantially parallel patterns of adhesive spaced from each other a first distance in the second dimension, then (c) is further practiced using a third roll of the second set rotatable about an axis substantially common with that of said second roll, and operatively spaced approximately the first distance from the second roll in the second dimension, so that the second and third rolls of the second set cooperate with the first roll of the second set to substantially simultaneously seal the two first patters of adhesive of the form. Where the form comprises two second substantially parallel patterns of adhesive spaced from each other a second distance in the first dimension, then (b) is further practiced to selectively rotate the first roll of the first set to come into contact with the form at both second patterns of adhesive to seal the form at both second patterns, but so as to substantially not come in contact with the form between the two second patterns of adhesive. When the form comprises a third second pattern of adhesive substantially parallel to both of the two second patterns of adhesive, disposed between the two second patterns in the first dimension, then (b) is further practiced to selectively rotate the first roll of the first set to come into contact with the form at all three of the second patterns of adhesive to seal the form at all three second patterns, but so as to substantially not come in contact with the form between the second patterns of adhesive.
In the preferred embodiment (a)-(c) are practiced so as to first move the form into operative association with the first set of rolls, and then into operative association with the second set of rolls. The invention also further comprises adjusting the positions of the second and third rolls of the second set with respect to each other along the common axis, to accommodate forms having different spacings between the second patterns of adhesive. The adjustment may be accomplished using any conventional mechanism or technique.
According to another aspect of the present invention a sealing apparatus is provided. The sealing apparatus comprises or consists of the following components: A first set of rolls comprising a first substantially continuous roll, and a second roll having a non-round shape with at least one projection, the first and second rolls mounted and positioned for rotation about substantially parallel axes and so that at a first position the at least one projection comes into operative association with the first roll to perform a sealing action, but the second roll besides the at least one projection not coming into operative association with the first roll, and at a second position the at least one projection is not in operative association with the first roll. A stepper motor operatively connected to the second roll of the first set so as to effect rotation thereof to move the at least one projection between the first and second positions. And a second set of rolls including a first substantially continuous roll having a first length and a second substantially continuous roll having a second length less than about half of the first length, the first and second rolls of the second set mounted and positioned for rotation about substantially parallel axes which are also parallel to the axes of the rolls of the first set of rolls.
Preferably the first set of rolls has a discharge which discharges material being sealed thereby in a first direction; and the second set of rolls is positioned substantially immediately adjacent the first set of rolls discharge in the first direction to receive material discharged from the discharge between the first and second rolls of the second set. Preferably the second set of rolls comprises the third roll substantially concentric with the second roll and rotatable about a substantially common axis, the third roll spaced from the second roll along the substantially common axis.
In order to provide a minimal amount of material while still having optimum operability, the second roll of the first set preferably has a configuration that in end view simulates an airplane propeller so that the at least one projection comprises first and second projections angularly spaced from each other about 180 degrees. Preferably the second roll of the first set is positioned above the first roll of the first set, and the first and second rolls are rotatable about substantially horizontal axes. Also, the stepper motor is typically connected to a microprocessor which controls the stepper motor.
In the normal use, the first and second sets of rolls are positioned and mounted so as to receive therebetween business forms having pressure activated adhesive, and the sets of rolls are capable of applying at least about 100 pounds of pressure per lineal inch to business forms disposed between the first and second rolls of each of the first and second sets of rolls.
According to yet another aspect of the present invention a set of pressure applying rolls per se is provided. The set of rolls comprises: A first substantially continuous roll rotatable about a first axis. A second non-round roll having a configuration that in end view substantially simulates an airplane propeller, including at least first and second projections angularly spaced from each other, and rotatable about a second axis substantially parallel to the first axis. The first and second rolls mounted and positioned so that at a first position one of the projections comes into operative association with the first roll to perform a sealing action, but the second roll besides the projections not coming into operative association with the first roll, and at a second position the projections are not in operative association with the first roll. And the second roll positioned above the first roll, and the first and second axes comprising substantially horizontal axes.
The first set of rolls also preferably comprises a stepper motor operatively connected to the second roll so as to effect rotation thereof to move the projections between the first and second positions. The second non-round roll may have exactly two projections angularly spaced from each other about 180xc2x0.
It is the primary object of the present invention to provide for the simple, versatile, and cost effective sealing of business forms having pressure activated adhesive, and apparatus for that purpose. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.